1. Field of the Invention
The present invention relates to a side tarpaulin tightener, such as used on a mounting structure of a utility motor vehicle for tensioning a tarpaulin, which includes a pivotal tension lever and a hook and adjustment unit separately pivotally articulated to the tension lever such that an upward closing pivotal movement of the tension lever causes an upward movement and an engagement of the hook under the mounting structure and an oppositely directed downward movement of the adjustment unit and tarpaulin attached thereto so as to tension the tarpaulin in a manner that avoids formation of folds in the tarpaulin.
2. Description of the Prior Art
Side tarpaulin tighteners are commonly used for tensioning a tarpaulin to a utility motor vehicle tarpaulin mounting structure. One prior art type of side tarpaulin tightener includes a tension lever-hook module having a tension lever and a hook. The tension lever is structured as a one-armed lever pivotably articulated about a pivot axis. The hook extends behind a stationary element that serves as an abutment against which a tarpaulin can be tensioned. The side tarpaulin tightener also includes means for the transmission onto the tarpaulin of a tensioning movement exerted by the tension lever.
Such prior art type of side tarpaulin tightener is known from German patent document No. DE 44 15 042 C1. The prior art side tarpaulin tightener disclosed in this document employs a tension lever-hook module which is disposed at the free end of an adjustable belt attached onto the tarpaulin. The tension lever-hook module includes a tension lever structured as a flap which is articulated on an approximately U-shaped subcomponent in the region of two parallel flanks thereof so as to be pivotable about a pivot axis. Also, a hook is formed on the subcomponent which serves for extending behind a stationary element, for example the lower edge of a frame profile of a utility motor vehicle mounting structure, that serves an abutment for the tarpaulin is to be tensioned. In an engaged condition of the hook, for example in which it extends behind the frame profile, the side of the subcomponent facing away from the tension lever rests on the outside of the tarpaulin and is supported on the outside of the frame profile. The pivot axis of the tension lever is formed by a pin about which the free end of the belt is wrapped forming a loop. The other end of the belt is attached to the tarpaulin to be tensioned. Spaced apart from its pivot axis, the tension lever has a tension bar in the region of a lever arm of the tension lever. The belt loop is guided across the tension bar on the tension lever. When pivoting the tension lever in a downward direction from an open position into a closed position, a tightening of the belt occurs due to the deflection of the belt loop across the tension bar spaced apart from the pivot axis. In its closed position the tension lever is held by a latching mechanism against an unintentional opening or snapping of the tension lever in an upward direction.
Even if this prior art side tarpaulin tightener is satisfactory and can be safely used, it has disadvantages which must nevertheless be accepted. Due to a manipulation of the tension belts, which cannot be excluded, such side tarpaulin tightener does not meet the prerequisites for use as a customs seal. Moreover, it may happen that the tension lever in its closed position is not latched as accordingly authorized. Due to the effect of the air stream, a flapping of the tarpaulin can occur in which the tarpaulin beats against the tension belt which, in turn, can lead to the tension lever snapping upward from its closed position. Consequently, the hook becomes detached from its engaged condition such that the entire tension lever-hook module disposed at the end of the tension belt is no longer secured in position and can swing freely at the outside, for example, of a utility motor vehicle mounting structure. For adjusting the side tarpaulin tightener with respect to the tensional force to be brought onto the tarpaulin, the free end forming the loop of the tension belt is correspondingly adjusted. Due to the textile material of the tension belts, an adjustment of the belt can only be carried out with difficulty in cold ambient temperatures due to the resulting stiffness of the material.
A further disadvantage of this prior art side tarpaulin tightener is that the handling of the tightener for causing its operation is only possible by using both hands. Opening the side tarpaulin tightener must be carried out with both hands since one hand must be used to release the latching mechanism as the other hand guides the movement of the tension lever in order to prevent uncontrolled upward snapping of the tension lever due to the tensile stress applied on it. The opened tension lever subsequently projects from the subcomponent abutting at its underside on the tarpaulin or the frame profile. Although, now with the side tarpaulin tightener in its opened position, tension stress is removed from the hook such that the hook can be brought out of its engaged condition in which it extends behind the frame profile, the hook continues to be in the same plane in which it extends behind the frame profile. If the tarpaulin must now be rolled upwardly in order to open the utility motor vehicle mounting structure, the individual side tarpaulin tighteners must first be swung out of their neutral position in contact on the frame profile, in order for the hooks not to extend behind the frame profile when the tarpaulin is lifted.
In the case of such prior art side tarpaulin tightener, during tensioning of the tightener by downward pivoting of the tension lever, the subcomponent supported on the outside of the tarpaulin together with the hook are moved upwardly in a vertical direction relative to the frame profile which brings the hook into the engaged condition in which it extends behind the frame profile. As a consequence of this movement and as the tarpaulin is being tensioned, a fold can form in the tarpaulin in front of the subcomponent such that the purpose for using the side tarpaulin tightener, namely the tensioning of a tarpaulin over its entire height, is counteracted. Such folds can lead to a flapping of the tarpaulin due to the air stream which is undesirable.
Consequently, there is a need for further development of a side tarpaulin tightener of the above type such that not only its handling ability for opening the tarpaulin is improved but also its tensioning of the tarpaulin without the formation of folds is possible.